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Kidney Week

Abstract: FR-PO969

Cyst Growth in the Anks6pR823W Model of ADPKD Is Reduced by the Anks3I454E Mutation

Session Information

Category: Genetic Diseases of the Kidney

  • 1001 Genetic Diseases of the Kidney: Cystic

Authors

  • Clark, Euan, University of Heidelberg, Mannheim, Germany
  • Gosmann, Christian, University of Heidelberg, Mannheim, Germany
  • Groene, Hermann-Josef, University of Heidelberg, Heidelberg, Germany
  • Gauguier, Dominique, INSERM, Paris, France
  • Bowie, James, University of California, Los Angeles, Los Angeles, California, United States
  • Hoffmann, Sigrid C., University of Heidelberg, Mannheim, Germany
Background

The Anks6R823W mutation in rats causes an ADPKD-like phenotype with massive renal cyst growth leading to kidney failure and death. Previously we demonstrated that this mutation prevents the Anks6-SAM domain from binding to the Anks3-SAM domain and disrupts the spatial expression of both proteins. Since Anks6-Anks3 binding prevents Anks3-Anks3 SAM domain interactions it is possible that increased formation of Anks3 homopolymers is part of the pathological process. Thus, we created a rat with an Anks3I454E mutation in the SAM domain where Anks3 can no longer bind to itself but can interact with Anks6.

Methods

The Anks3I454E mutation was generated using CRISPR-Cas9 in Sprague Dawley rats. Clinical parameters in 24-h urine and blood plasma were determined to evaluate renal function. Histological analysis and western blots were performed by standard techniques. These rats were crossed into the TGR-CMV-Anks6pR823W line and the kidneys of the offspring investigated at 2 and 4 weeks. Cysts were counted and scored using a 4 point scale.

Results

No histological abnormalities were observed in the kidneys of Anks3I454E/I454E rats up to 1 year of age. There was an increase in urine osmolarity and a decrease in the concentration of plasma parameters in these rats, probably due to increased water reabsorption in the kidney, supported by an increase in aquaporin 2 expression. In TGR-CMV-Anks6pR823WAnks3WT rats, cyst growth started within the first 10 days after birth leading to massive kidney hypertrophy. In both the 2 and 4 week old TGR-CMV-Anks6pR823W carrying the Anks3I454E mutation there was a significant reduction in the kidney to body weight ratio and cyst score with the largest reduction in Anks3I454E/I454E rats versus TGR-CMV-Anks6pR823WAnks3WT rats (2 weeks: kw/bw p=0.0003, cyst score p=0.0001; 4 weeks: kw/bw p=0.0086, cyst score p=0.0001).

Conclusion

1) The disruption of Anks3-Anks3 binding via the SAM domain is not pathological in rats and causes increased water reuptake in the kidney. 2) The disruption of Anks3-Anks3 binding in the Anks6pR823W rat model of ADPKD significantly reduces the rate of cyst growth and this effect is increased in Anks3I454E homozygous versus heterozygous rats. This study was supported by the grant of the NIH (5RO1DK100482) to JB and SH.

Funding

  • NIDDK Support